At present, restricted by the fact that radio access technology (RAT) replacement from Universal Mobile Telecommunications System (UMTS) RAT to Long Term Evolution (LTE) RAT is a long-term project, the operators cannot stop UMTS RAT's network immediately, and LTE RAT will coexist with UMTS RAT for a period of time. Thus, a time-division spectrum allocation solution, such as dynamic spectrum sharing method or semi-dynamic spectrum sharing method, is utilized to switch the spectrum of a cell between LTE RAT and UMTS RAT alternately accordingly to a certain parameter. For example, in the semi-dynamic spectrum sharing method, the spectrum is released from UMTS RAT and allocated to LTE RAT when UMTS RAT is supposed to have a low traffic; and the spectrum is released from LTE RAT and allocated to UMTS RAT when UMTS RAT is supposed to have a high traffic. In the dynamic spectrum sharing method, the spectrum is allocated according to a load of UMTS in a transmission time interval (TTI). For example, the spectrum can be allocated to LTE RAT when UMTS RAT is supposed to have a low load and be allocated to UMTS RAT when UMTS RAT is supposed to have a high load.
FIG. 1 illustrates a prior art system in which spectrum of a cell is allocated to a LTE RAT and a UMTS RAT alternately in a time-division manner. Suppose a user equipment (UE) operates in LTE pattern, and the spectrum of primary-serving cell is allocated to LTE RAT initially. The UE measures a downlink cell reference signal (CRS) and feedbacks the measurement result to the primary-serving cell via uplink channel periodically. However, in a time-division spectrum sharing situation, the spectrum of primary-serving cell is allocated to UMTS RAT with a same frequency-band from t2 to t3, for example. In this case, the measurement result of CRS in any time slot from t2 to t3 is wrong, and wrong measurement result is feedback to the primary-serving cell by UE. Therefore, accuracy and efficiency of downlink scheduling are reduced.